1) Field of the Invention
The present invention relates to burner caps, and more particularly, to a burner cap used on a gas cooktop and having a flame stabilization chamber therein.
2) Description of Prior Art
Atmospheric gas burners are commonly used as surface units in household gas cooking appliances. A significant factor in the performance of gas burners is their ability to withstand airflow disturbances in the surroundings, such as room drafts, rapid movement of cabinet doors, and most commonly rapid oven door manipulation. Manipulation of the oven door is particularly troublesome because rapid openings and closings of the oven door often produce respective under-pressure and over-pressure conditions within the range body. Since the flue, through which combustion products are removed from the oven, is sized to maintain the desired oven temperature and is generally inadequate to supply a sufficient airflow for re-equilibration, a large amount of air passes through or around the gas burners.
This surge of air around the gas burners is detrimental to the flame stability of the burners and may cause extinction of the flames. This flame stability problem is particularly evident in sealed gas burner arrangements, referring to the lack of an opening in the cooktop surface around the base of the burner to prevent spills from entering the area beneath the cooktop.
The inherent cause of this flame instability is the low pressure drop of the gas-air mixture passing through the burner ports of a typical rangetop burner. Although there is ample pressure available in the fuel, the pressure energy is used to accelerate the fuel to the high injection velocity required for primary air entrainment. Relatively little of this pressure is recovered at the burner ports. A low pressure drop across the ports allows pressure disturbances propagating through the ambient to easily pass through the ports, momentarily drawing the flame towards the burner head and leading to thermal quenching and extinction.
An additional problem is that rapid adjustments of the fuel supply to a gas burner from a high burner input rate to a low burner input rate often will cause flame extinction when the momentum of the entrained air flow continues into the burner even though fuel has been cut back, resulting in a momentary drop in the gas-air ratio, causing extinction.